Valve having an eccentric butterfly member and sealing element for said valve

ABSTRACT

A valve of the type having an axial bore and an annular radial bearing surface and two radially extending bearings in the body for receiving two journals carrying a butterfly member which is eccentric relative to the journals. A sealing element is disposed in the bore and has a cylindrical sleeve portion and, at one end, an outer radial bearing surface for bearing against the valve body and a beading which extends radially inwardly against which the butterfly member bears in the closing position and, in the middle of the sealing element, two diametrally opposed coaxial passageways for the journals. The distance between the axis of the passageways and the bearing surface of the sealing element in the free state of the sealing element exceeds the distance between the axis of the bearings and the bearing surface of the valve body and the diameter of the passageways of the sealing element in the free state of the sealing element is less than the diameter of the journals.

United States Patent 91 [111 3,776,509

Leblond Dec. 4, 1973 VALVE HAVING AN ECCENTRIC Primary ExaminerHenry T.Klinksiek BUTTERFLY MEMBER AND SEALING ELEMENT FOR SAID VALVE [75]Inventor: Christian Leblond, Atton, France [73] Assignee: Pont-A-MoussonS.A.,

Pont-A-Mousson, France [22] Filed: Feb. 27,1973

[21] Appl. No.: 336,294

[30] Foreign Application Priority Data Mar. 22, 1972 France 7209970 [52][1.8. CI. 251/306 [51] Int. Cl. F16k l/226 [58] Field of Search [56]References Cited UNITED STATES PATENTS 3,473,784 10/1969 Radford 251/306Att0rneyRichard C. Sughrue et al.

[57] ABSTRACT A valve of the type having an axial bore and an annularradial bearing surface and two radially extending bearings in the bodyfor receiving two journals carrying a butterfly member which iseccentric relative to the journals. A sealing element is disposed in thebore and has a cylindrical sleeve portion and, at one end, an outerradial bearing surface for bearing against the valve body and a beadingwhich extends radially inwardly against which the butterfly member bearsin the closing position and, in the middle of the sealing element, twodiametrally opposed coaxial passageways for the journals. The distancebetween the axis of the passageways and the bearing surface of thesealing element in the free state of the sealing element exceeds thedistance between the axis of the bearings and the bearing surface of thevalve body and the diameter of the passageways of the sealing element inthe free state of the sealing element is less than the diameter of thejournals.

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r i a; 8 ii i 5 14 19 D1 D2 J7 5 a 1i 1a 1 {1 a l i g i VALVE HAVING ANECCENTRIC BUTTERFLY MEMBER AND SEALING ELEMENT FOR SAID VALVE Thepresent invention relates to a valve having an eccentric butterflymember of the type comprising a valve body having an axial bore and aradial annular bearing surface, a butterfly member which is carried byjournals received in radial bearings associated with the valve body andis eccentric with respect to said journals, and a sealing element havinga cylindrical sleeve portion and disposed in the bore of the valve bodyand having, at one end, an outer radial annular surface for bearingagainst the valve body and a radially inwardly projecting beadingagainst which beading the butterfly member bears in the closingposition, and, in the midpart of the sealing element, two diametricallyopposed passageways for the passage of the journals.

Valves of this type are already known, for example from the FrenchPatent Application filed by the Applicant under N0. 71,31 290, but thedistance between the axis of the bearings and the bearing surface of thevalve body is equal to the distance between the axis of the passagewaysin the sealing element and its bearing surface in the free state, andthe diameter of these passageways, with the sealing element in the freestate, is equal to that of the journal.

Now, a seal between the journals and the bearings is difficult toachieve, in particular when the difference between the fluid pressuresof the fluid in the valve on each side of the butterfly member, when thelatter is in the closing position, is excessive, the higher of saidpressures tending to shift the butterfly member and its journals awayfrom the elastic sealing rings usually mounted in the bearings. Thecontact between the pas sageways of the sealing element and the journalsmust be fluidtight even in the presence of this pressure difference.

This seal is suitable when the valve is mounted between pipe flanges thediameter of which is equal to the nominal diameter of the valve forwhich the latter has been constructed, namely the inside diameter of thesealing element. On the other hand, this is no longer so when the flangemounted adjacent the beading of the sealing element, which is usuallythe downstream flange with respect to the direction of flow of thefluid, has a larger diameter, since under the effect of an excessivepressure difference, the beading flows in the downstream direction andthe walls of the passageways come away from the journals and thus resultin leakages.

An object of the present invention is to avoid this drawback.

The invention provides a valve of the above-defined type, wherein thedistance between the axis of the passageways and the bearing surface ofthe sealing element in the free state exceeds the distance between theaxis of the bearings and the bearing surface of the valve body and thediameter of the passageways of the sealing element in the free state isless than the diameter of the journals.

Thus, even when the sealing element is distorted in the downstreamdirection, the thickness of the rubber applied against the downstreamside of the journals is still enough to ensure a seal between thesejournals and their bearings.

Another object of the invention is to provide a sealing element for thevalve having the same features as those mentioned hereinbefore asconcerns the distances and the diameters.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawing.

In the drawing FIG. 1 is a diametral sectional view through the axes ofthe journals of a valve having an eccentric butterfly member accordingto the invention mounted between two flanges;

FIG. 2 is a partial diametral sectional view of the sealing element of.the valve shown in the free state;

FIG. 3 is a partial diametral sectional view to an enlarged scale of thevalve shown in FIG. 1 when the valve is closed but not in service, and

FIG. 4 is a view similar to FIG. 3 when the valve is closed and inservice.

The valve shown in the drawing is of the type described and shown in theaforementioned Patent Application and comprises a valve body 1, abutterfly member 2 carried by journals 3 and a rubber sealing element 4disposed in the valve body. The valve body 1 has for this purpose anaxial bore 5 and, at both ends of the latter, annular cavities 6 havingat their radially outermost part a recessed or re-entrant portion 7, theradial annular surfaces 8 of the cavities located outside the recessedportion 7 constituting bearing surfaces for the sealing element. Thecontact area of the bearing surface 8 is extended by an inwardlyprojecting annular radial lip. The journals 3 are received in radialbearings 9 of the valve body which have an axis X-X, with interpositionof elastically yieldable sealing sleeves 10 and the butterfly member 2is eccentric with respect to these journals. The sealing element 4comprises a cylindrical sleeve portion and at each axial end of theelement, an annular outer radial flange 11 having at its end an inneraxial flange 12 which defines an annular radial bearing surface 13 andan annular inner radial beading 14 so that the section of the sealingelement has roughly the shape of an H. The flanges 11 are engaged in thecavities 6 of the valve body and the flanges 12 in the recessed portions7 of the cavities with in particular a mutual bearing contact betweenthe surfaces 8 and 13 which hooks the sealing element to the body. Thesealing element has in its middle two diametrally opposed passageways 15through which the journals 3 extend.

As shown in FIG. 2, the passageways in the sealing element 4 have, whenthe latter is in the free state, an axis YY and a diameter d and, asshown in FIG. 3, in which the contour in the free state of the sealingelement is shown in dot-dash line, the diameter d of the passageways ofthe sealing element in the free state is less than the diameter D of thejournals and the distance L between the axis YY of the passageways andthe bearing surface 13 of the sealing element in the free In theparticular embodiment described, the valve body is substantiallysymmetrical with respect to a diametral plane through the axis X-X ofthe bearings and the sealing element is on the whole also substantiallysymmetrical with respect to this plane, although the axis Y-Y of thepassageways of the sealing element are offset a distance x in theupstream direction with respect to this plane of symmetry.

The absolute symmetry of the valve body and the sealing element isslightly disturbed by the extended lip on the bearing surface 8 and thecorresponding annular pocket formed adjacent the bearing surface 13 toaccommodate the lip.

The valve is mounted between two flanges 16 which are fixed to the endsof the two pipes 17 which extend half-way into the flanges, the latterbeing connected to the pipes by a mechanical welding along weld beads18, the inner bead of which has a flank or side at 45. The pipe 17 has anominal diameter D for which the valve has been constructed but as theflanges 16 have an inside diameter D exceeding the diameter D thereexists between the weld beads 18 and the end faces of the flanges 11 ofthe sealing element an empty annular space 19.

Thus, the downstream beading 14 can flow towards the space 19 when thepressure prevailing upstream of the sealing element urges the beading inthe downstream direction. In this deformation of the sealing element,the downstream portion of the wall of the passageways could, if thepreceding relations between d and D, on one hand, the l and L, on theother hand, were not provided, be shifted away from the journals to anextent to allow a leakage of fluid. Indeed, the downstream beading 14 issubjected to an appreciable force due to the pressure prevailing in theempty annular space 20 between the outer contour of the butterfly memberand the downstream inner profile 21 of the beading 14.

However, the passageway diameter d in the free state of the sealingelement is less than the diameter D of the journals and, upon assembly,there is consequently a tight contact S on the upstream side and a tightcontact S on the downstream side, namely a diarnetral tight fit S Sbetween the sealing element and the journals. Further, as the axis YY ofthe passageway in the free state is offset a distance x L l with respectto the axis X-X of the journals in the upstream direction, that is tosay toward the side where usually the highest pressure is exerted whenthe valve is closed, the downstream tight contact force S is greaterthan the upstream tight contact force S.

As shown in FIG. 3, when this greater pressure is exerted on thedownstream beading 14 there is produced in the direction of the annularspace 19 a flow of the sealing element accompanied by a hollowing of theupstream inner profile 21 of the beading and a downstream displacementof the region of the sealing element which surrounds the downstream partof the wall of the passageways, this'displacement increasing theupstream tightness and decreasing the downstream tightness.

The values of the tight contacts are materialized in FIGS. 3 and 4 bythe length of the arrows f and f in respect of FIG. 3 and f and f inrespect of FIG. 4, which are applied to the upstream and downstreamparts of the walls of the passageways. The deviations S and S of FIG. 3between the positions in the free state and in the mounted state of saidupstream and downstream parts correspond to the arrows j and f and, byanalogy, solely to show the evolution of the tight fits when the valveis in service, theoretical deviations S and S are shown in FIG. 4.

The difference D d of the diameters and the offset x in the upstreamdirection are such that the downstream tight fit under the highestpressure to which the valve may be exposed remains sufficient topreclude any separation between the downstream part of the wall of thepassageways and the journals which would result in leakage.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is 1. In a valve comprising a valve bodydefining an axial bore and an annular radial bearing surface, tworadially extending coaxial bearings in the valve body, an eccentricbutterfly member, two journals received in the bearings of the valvebody and carrying the butterfly member, the butterfly member beingeccentric with respect to said journals, and a sealing elementcomprising a cylindrical sleeve portion which is disposed in the bore ofthe valve body and has at one end an outer annular radial bearingsurface for bearing against the annular radial bearing surface of thevalve body and a beading which extends radially inwardly of said bearingsurface, against which beading the butterfly member is adapted to bearin the valve closing position and, in the middle part of the sealingelement, two diametrally opposed coaxial passageways for the passage ofthe journals; the improvement characterized by the distance between theaxis of the passageways and the bearing surface of the sealing elementin the free state of the sealing element exceeding the distance betweenthe axis of the bearings and the bearing surface of the valve body, andthe diameter of the passageways of the sealing element in the free stateof the sealing element being less than the diameter of the journals.

2. A valve as claimed in claim 1, having a valve body which issymmetrical with respect to a plane perpendicular to said axial bore andhas a sealing element which is substantially symmetrical with respect toa plane perpendicular to said axial bore, the axis of the passageways ofthe sealing element in the free state of the sealing element beingoffset in the axial direction with respect to its plane of symmetry.

3. In a sealing element for a valve comprising a valve body defining anaxial bore and an annular radial bearing surface, two radially extendingcoaxial bearings in the valve body, an eccentric butterfly member, twojournals received in the bearings of the valve body and carrying thebutterfly member, the butterfly member being eccentric with respect tosaid journals, said sealing element comprising a cylindrical sleeveportion having an axis and for disposing in the bore of the valve bodycoaxially with said bore and at one end an outer annular radial bearingsurface for bearing against the valve body and a radially inwardlyprojecting beading against which beading the butterfly member is adaptedto bear in the closed position of the valve, and, in the middle part ofthe sealing element, two diametrally opposed passageways for the passageof the journals the feature that the distance between the axis of thepassageways and the bearing surface of the sealing element in the freestate of the sealing element exceeds the distance between the axis ofthe bearings and the bearing surface of the valve body and the diameterof the pasa plane perpendicular to the axis of the sealing element,wherein in the free state of the sealing element the axis of thepassageways is offset in the axial direction with respect to the planeof symmetry of the sealing eleto a plane perpendicular to the axialbore, the sealing 5 ment.

element being substantially symmetrical with respect to

1. In a valve comprising a valve body defining an axial bore and anannular radial bearing surface, two radially extending coaxial bearingsin the valve body, an eccentric butterfly member, two journals receivedin the bearings of the valve body and carrying the butterfly member, thebutterfly member being eccentric with respect to said journals, and asealing element comprising a cylindrical sleeve portion which isdisposed in the bore of the valve body and has at one end an outerannular radial bearing surface for bearing against the annular radialbearing surface of the valve body and a beading which extends radiallyinwardly of said bearing surface, against which beading the butterflymember is adapted to bear in the valve closing position and, in themiddle part of the sealing element, two diametrally opposed coaxialpassageways for the passage of the journals; the improvementcharacterized by the distance between the axis of the passageways andthe bearing surface of the sealing element in the free state of thesealing element exceeding the distance between the axis of the bearingsand the bearing surface of the valve body, and the diameter of thepassageways of the sealing element in the free state of the sealingelement being less than the diameter of the journals.
 2. A valve asclaimed in claim 1, having a valve body which is symmetrical withrespect to a plane perpendicular to said axial bore and has a sealingelement which is substantially symmetrical with respect to a planeperpendicular to said axial bore, the axis of the passageways of thesealing element in the free state of the sealing element being offset inthe axial direction with respect to its plane of symmetry.
 3. In asealing element for a valve comprising a valve body defining an axialbore and an annular radial bearing surface, two radially extendingcoaxial bearings in the valve body, an eccentric butterfly member, twojournals received in the bearings of the valve body and carrying thebutterfly member, the butterfly member being eccentric with respect tosaid journals, said sealing element comprising a cylindrical sleeveportion having an axis and for disposing in the bore of the valve bodycoaxially with said bore and at one end an outer annular radial bearingsurface for bearing against the valve body and a radially inwardlyprojecting beading against which beading the butterfly member is adaptedto bear in the closed position of the valve, and, in the middle part ofthe sealing element, two diametrally opposed passageways for the passageof the journals : the feature that the distance between the axis of thepassageways and the bearing surface of the sealing element in the freestate of the sealing element exceeds the distance between the axis ofthe bearings and the bearing surface of the valve body and the diameterof the passageways of the sealing element in the free state of thesealing element is less than the diameter of the journals.
 4. A sealingelement as claimed in claim 3, for a valve having a valve body which issymmetrical with respect to a plane perpendicular to the axial bore, thesealing element being substantially symmetrical with respect to a planeperpendicular to the axis of the sealing element, wherein in the freestate of the sealing element the axis of the passageways is offset inthe axial direction with respect to the plane of symmetry of the sealingelement.